1. Field of the Invention
A heat sealing machine for joining a battery casing and battery cover.
2. Description of the Prior Art
Various efforts have been made to secure battery covers to battery casings where such covers and casings are constructed of thermo-plastic material. The cover and casing are often joined together in a sealing manner by melting portions of the cover and the casing by heating the cover and casing and joining the melted portions together under pressure.
Unfortunately, in the case of batteries having the poles and connecting bars inserted beforehand and the electrode plates connected thereto, it is not possible to use the heating plate because of the complexity of the construction of the connectiong bars and electrode plates existing on the inner side of the cover. This necessitates bonding the cover and the casing together with an adhesive material. However, the liquid integrity of the bonded seams is poor, so the electrolyte is apt to flow into adjacent cells. Moreover, this method of assembly is relatively inefficient.
Examples of the prior art are found in U.S. Pat. Nos. 3,441,448, 3,556,862, 3,629,010, 3,778,314, 3,909,300, 4,010,537, 4,025,371, 4,071,661, 4,171,564, 4,306,355, and 4,375,127.